Printed from: https://www.conservationhandbooks.com/hedging/trimming/trimming-and-laying/
In the past, farm hedges were managed by regular hand trimming, and then once they had started to thin and lose vigour, were allowed to grow up to a height of between 8-12’ before laying. In stock-raising or dairy-producing areas, prior to the introduction of barbed wire, this would have been done every 10-15 years...